Optimising theatre utilisation through Lean Six Sigma: A model for sustainable theatre utilisation improvement.

Abstract

Background: This quality improvement study was undertaken in the ophthalmology theatres at the Western Eye Hospital, Imperial College Healthcare NHS Trust, to address reduced capped theatre utilisation during the COVID-19 recovery period. Baseline utilisation was 75.8%, below the national Getting It Right First Time target of 85% for theatre touchtime utilisation by 2024/25. The aim was to identify the causes of underperformance and implement targeted interventions to improve theatre efficiency.

Methods: A Lean Six Sigma DMAIC (Define, Measure, Analyse, Improve, Control) framework was used as the study design. Targeted interventions included increasing pre-assessment capacity to reduce under-booking, improving scheduling processes, reducing early finishes, and carrying out structured daily reviews of implant and equipment availability to minimise on-the-day cancellations. Multiple regression, factorial Design of Experiments, process capability analysis, Plan-Do-Study-Act cycles, and Statistical Process Control were used to analyse variation, test changes, and monitor performance.

Results: The Analyse phase showed that early finishes, under-booking, and limited pre-assessment capacity were the main drivers of low utilisation, rather than commonly assumed factors such as late starts. Following the introduction of targeted interventions, capped theatre utilisation improved from 75.8% to 81%. Continuous monitoring through Plan-Do-Study-Act cycles and Statistical Process Control supported stability and informed further refinements.

Conclusions: This project shows that combining Lean Six Sigma methodology with advanced statistical analysis can deliver measurable improvements in theatre utilisation. The findings challenged long-held assumptions about the causes of inefficiency and highlight the importance of optimising scheduling processes and pre-assessment capacity. The model offers a transferable, scalable approach for other units aiming to enhance theatre efficiency and achieve sustainable operational improvements.